In this study, we have examined the impact of film thickness on the piezoelectric performance of polyvinylidene fluoride (PVDF) and PVDF nanocomposite film-based piezoelectric nanogenerator (PENG). For this, hexagonal-boron nitride (h-BN) nanoparticles were synthesized via a hydrothermal method, and their characteristics were analyzed using X-ray diffraction (XRD) and Raman spectroscopy. Films of varying thicknesses were formed by mixing PVDF with 1 wt% of h-BN nanoparticles. These films were then characterized using FTIR spectroscopy, to evaluate the β-phase content. The value of β-phase content obtained for 50 μm, 100 μm, and 200 μm PVDF films was found to be 54%, 57%, and 58% and 71%, 75%, and 77% for the h-BN/PVDF nanocomposite films, respectively. The increased relative β-phase content contributes to an increased piezoelectric performance. The energy harvesting performance of these films was then systematically evaluated by tapping them with the help of electrodynamic shaker, which shows that greater the thickness of the film, the higher is the voltage as well as the current generated. Our findings shed light on the relationship between film thickness and energy harvesting efficiency in h-BN filled PVDF composites, providing valuable insights for the design and optimization of piezoelectric energy harvesting devices.